Three different projects are included in our research program. Dr. Atkinson's project concerns the identification of surface antigens peculiar to the type II epithelial cell of the lung. Her model system is that of the mouse. Inbred animals are used. Immune sera, specific for the type II epithelial cell, are the major probes on which biological, biochemical and morphological studies are based. Dr. Hewitt is concerned with aging processes. Specifically, he is studying changing patterns of specific enzymes as a consequence of aging. His system is that of the mouse supplemented with similar studies using Drosophila. Dr. Tan's work is directed towards the purification of exo-enzymes from a special strain of Aspergillus niger. He is studying the biosynthesis and secretion of exo-carbohydrases.